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Abstract:

A hard disk drive including a plurality of magnetic disks and a voice
coil motor. The voice coil motor includes a coil and a first damper plate
for dampening vibrations generated by the coil. The first damper plate is
disposed within the voice coil motor.

Claims:

1. A hard disk drive comprising: a plurality of magnetic disks; and a
voice coil motor comprising: a coil; a first damper plate for dampening
vibrations generated by said coil, wherein said first damper plate is
disposed within said voice coil motor.

2. The hard disk drive of claim 1, wherein said voice coil motor further
comprises: a top yoke, wherein said first damper plate is disposed
adjacent said top yoke.

3. The hard disk drive of claim 1, wherein said voice coil motor further
comprises: a first magnet disposed adjacent said top yoke, wherein said
first damper plate is disposed coplanar with said first magnet.

4. The hard disk drive of claim 1, wherein said first damper plate
comprises: an adhesive material for adhering said first damper plate to
said top yoke.

5. The hard disk drive of claim 1, wherein said voice coil motor further
comprises: a plurality of posts on a top yoke for aligning a first magnet
and said first damper plate with said top yoke.

6. The hard disk drive of claim 1, wherein said first damper plate
comprises: a projection that protrudes beyond a periphery of said top
yoke.

7. The hard disk drive of claim 1, wherein said voice coil motor further
comprises: a second damper plate for dampening vibrations generated by
said coil; and a bottom yoke, wherein said second damper plate is
disposed adjacent said bottom yoke.

8. The hard disk drive of claim 7, wherein said voice coil motor further
comprises: a second magnet disposed adjacent said bottom yoke, wherein
said second damper plate is disposed coplanar with said second magnet.

9. The hard disk drive of claim 7, wherein said second damper plate
comprises: an adhesive material for adhering said second damper plate to
said bottom yoke.

10. The hard disk drive of claim 7, wherein said voice coil motor further
comprises: a plurality of posts on said bottom yoke for aligning said
second magnet and said second damper plate with said bottom yoke.

11. The hard disk drive of claim 7, wherein said second damper plate
comprises: a projection that protrudes beyond a periphery of said bottom
yoke.

12. The hard disk drive of claim 7, wherein said first damper plate and
said second damper plate are rigid.

13. The hard disk drive of claim 1, further comprising: a top cover; and
a damper, wherein said damper is disposed between said top cover and said
top yoke to reduce vibrations generated by said coil.

14. A voice coil motor comprising: a top yoke; a coil; a first magnet
disposed adjacent said top yoke; a first damper plate for dampening
vibrations generated by said coil, wherein said first damper plate is
disposed within said voice coil motor coplanar with said first magnet.

15. The voice coil motor of claim 14, further comprising: a bottom yoke;
a second magnet disposed adjacent said bottom yoke; a second damper plate
for dampening vibrations generated by said coil, wherein said second
damper plate is disposed within said voice coil motor coplanar with said
second magnet.

Description:

BACKGROUND

[0001] It is a goal to provide large-capacity magnetic disk devices or
hard disk drives (HDDs). One way to do this is to provide a greater
number of magnetic disks. However, it also a goal to provide narrower or
slimmer HDDs. Accordingly, when there are a greater number of magnetic
disks, there are also more actuator arms. As a result, the mass of
actuators increases. Consequently, the reaction force produced in a top
yoke and bottom yoke of a voice coil motor (VCM) by the actuator coils is
further increased during reading/writing. This reaction force causes the
top yoke and bottom yoke to vibrate, while also causing the device itself
to vibrate.

[0008] FIGS. 7A and B illustrate embodiments of a second damper plate.

[0009] The drawings referred to in this description should be understood
as not being drawn to scale except if specifically noted.

DESCRIPTION OF EMBODIMENTS

[0010] Reference will now be made in detail to embodiments of the present
technology, examples of which are illustrated in the accompanying
drawings. While the technology will be described in conjunction with
various embodiment(s), it will be understood that they are not intended
to limit the present technology to these embodiments. On the contrary,
the present technology is intended to cover alternatives, modifications
and equivalents, which may be included within the spirit and scope of the
various embodiments as defined by the appended claims.

[0011] Furthermore, in the following description of embodiments, numerous
specific details are set forth in order to provide a thorough
understanding of the present technology. However, the present technology
may be practiced without these specific details. In other instances, well
known methods, procedures, components, and circuits have not been
described in detail as not to unnecessarily obscure aspects of the
present embodiments.

[0012] As described above, it is a goal to provide large-capacity magnetic
disk devices or hard disk drives (HDDs). One way to do this is to provide
a greater number of magnetic disks. However, it also a goal to provide
narrower or slimmer HDDs. Accordingly, when there are a greater number of
magnetic disks, there are also more actuator arms. As a result, the mass
of actuators increases. Consequently, the reaction force produced in a
top yoke and bottom yoke of a voice coil motor (VCM) by the actuator
coils is further increased during reading/writing. This reaction force
causes the top yoke and bottom yoke to vibrate, while also causing the
device itself to vibrate.

[0013] In various embodiments, vibrations of an HDD are reduced, while the
HDD can also be made slimmer.

[0014] In one embodiment, a damper plate is provided at least on the
surface of the top yoke facing the actuator coil in order to reduce
vibration of the HDD. Accordingly, the thickness of the HDD is reduced.

[0016] Disk pack 102 includes a plurality of magnetic disks. In one
embodiment, disk pack 102 includes at least three magnetic disks.
Actuator 106 is associated with the top disk in disk pack 102. Moreover,
a plurality of other actuators (not shown) are associated with the
plurality of other disks in disk pack 102.

[0018] Top cover 105 is hermetically sealed to base 104 such that
contaminants do not enter HDD 100 and negatively affect the performance
of HDD 100.

[0019] Top yoke 112 and bottom yoke 113 are attached together via screws
116 and 117. Moreover, the combination of top yoke 112 and bottom yoke
113 are attached to base 104 via screws 116 and 117. In one embodiment, a
space 124 is provided between bottom yoke 113 and base 104. In another
embodiment, there is no space between bottom yoke 113 and base 104.

[0020] It should be appreciated that other fastening means may be used
instead of screws 116 and 117. Also, other screws or fastening means may
be used in addition to screws 116 and 117.

[0021] Actuator coil 120 is positioned between top yoke 112 and bottom
yoke 113. Actuator 106 is designed to be rotated (via actuator coil 120)
about a pivot 108 by means of the magnetic force of first magnet 122 and
second magnet 123. It should be appreciated that actuator coil 120
generates vibrations to VCM 100 (in particular top yoke 112 and bottom
yoke 113) that negatively affect the performance of HDD 100.

[0022] First damper plate 130 and second damper plate 132 are for reducing
the vibrations generated by actuator coil 120. First damper plate 130 and
second damper plate 132 are disposed inside the VCM 110. In particular,
first damper plate 130 is disposed on a surface (e.g., bottom surface) of
top yoke 112 that faces actuator coil 120. Similarly, second damper plate
132 is disposed on a surface (e.g., top surface) of bottom yoke 113 that
faces actuator coil 120. As a result, the space between top yoke 112 and
top cover 105, and the space between bottom yoke 113 and base 104 can be
reduced. Therefore, the thickness of HDD 100 is reduced.

[0023] First damper plate 130 increases the stiffness of top yoke 112 and
second damper 132 increases the stiffness of bottom yoke 113. Therefore,
vibrations of HDD 100, and, in particular, VCM 110 are reduced.

[0024]FIG. 3 depicts an isometric view of first damper plate 130 and
second damper plate 132 disposed on top yoke 112 and bottom yoke 113,
respectively.

[0025]FIG. 4 is an embodiment of an exploded view of FIG. 3. First damper
plate 130 is disposed adjacent first magnet 122. In particular, first
damper plate 130 is disposed closer to the periphery of HDD 100 than
first magnet 122. Similarly, second damper plate 132 is disposed adjacent
second magnet 123. In particular, second damper plate 132 is disposed
closer to the periphery of HDD 100 than second magnet 123.

[0026]FIG. 5A depicts top yoke 112, first magnet 122, first damper plate
130 and projections 140. Projections 140 are for positioning first magnet
122 and first damper plate 130 with respect to top yoke 112.

[0028] First magnet 122 and second magnet 123 are disposed in such a way
as to press against the projections 140 and 141, respectively.

[0029] Furthermore, first damper plate 130 and second damper plate 132 are
disposed further from pivot 108 than first magnet 122 and second magnet
123, respectively. In other words, first damper plate 130 and second
damper plate 132 are provided at the end of base 104 on the near side
from top yoke 112 and first magnet 122 and second magnet 123 are provided
on the side which is closer to pivot 108.

[0030] FIGS. 6A and B depict embodiments of first damper plate 130. In one
embodiment, first damper plate 130 comprises a coated part 150 which is
coated with adhesive (e.g., double-sided adhesive tape with low outgas,
acrylic adhesive of thickness 0.05 mm, etc), a hook part 155 which is
provided in such a way as to jut out from the outermost periphery of top
yoke 112. Hook part 155 can be used to facilitate in manually maneuvering
the placement of top yoke 112. For example, a grasping device (e.g.,
tweezers) can grasp onto hook part 155 and because first damper plate 130
is attached to top yoke 112, both top yoke 112 and first damper plate 130
can be manually maneuvered.

[0031] Circular cutaways 160 are slightly larger in diameter than
projections 140. First damper plate 130 is disposed in a position such
that circular cutaways 160 and projections 140 are concentric.

[0032] FIGS. 7A and B depict embodiments of second damper plate 132. In
one embodiment, second damper plate 132 comprises a coated part 152 which
is coated with adhesive (e.g., double-sided adhesive tape with low
outgas, acrylic adhesive of thickness 0.05 mm, etc), a hook part 157
which is provided in such a way as to jut out from the outermost
periphery of bottom yoke 113. Hook part 157 can be used to facilitate in
manually maneuvering the placement of bottom yoke 113. For example, a
grasping device (e.g., tweezers) can grasp onto hook part 157 and because
second damper plate 132 is attached to bottom yoke 113, both bottom yoke
113 and second damper plate 132 can be manually maneuvered.

[0033] Circular cutaways 162 are slightly larger in diameter than
projections 141. Second damper plate 132 is disposed in a position such
that circular cutaways 162 and projections 141 are concentric.

[0034] First damper plate 130 and second damper plate 132 are rigid. In
one embodiment, first damper plate 130 and second damper plate 132 are
formed from a material which is more rigid than aluminum (e.g., stainless
steel plate of thickness 0.5 mm).

[0035] In one embodiment, only first damper plate 130 is provided when
bottom yoke 113 is fixed to base 104 and bottom yoke 113 and base 104 are
in contact without a space 124 therebetween.

[0036]FIG. 8 depicts one embodiment of HDD 100 along A-A' in FIG. 1. FIG.
8 depicts top bosses 170 and bottom bosses 175. Top bosses 170 are
disposed between top cover 105 and top yoke 112. Bottom bosses 175 are
disposed between base 104 and bottom yoke 113.

[0037] In various embodiments top bosses 170 and bottom bosses 175 are
made of rubber (e.g., same material as used for gasket (not shown)
between base 104 and top cover 105). Both ends of bottom yoke 113 are
fixed by screws 116 and 117. The bottom surface bottom yoke 113 is fixed
by bottom bosses 175. Therefore, vibrations can be adequately reduced
with only first damper plate 113.

[0038] Moreover, the reaction force produced by vibration of actuator coil
120 on top yoke 112 is absorbed to some extent by top bosses 170 provided
on top cover 105.

[0039] Various embodiments of the present invention are thus described.
While the present invention has been described in particular embodiments,
it should be appreciated that the present invention should not be
construed as limited by such embodiments, but rather construed according
to the following claims.